linux-kernel - Re: [PATCH 1/1] kconfig: warn if an unknown symbol is selected

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Date:	Mon, 03 Nov 2014 12:38:11 +0100
From:	Paul Bolle <pebolle@...cali.nl>
To:	"Yann E. MORIN" <yann.morin.1998@...e.fr>
Cc:	Michal Marek <mmarek@...e.cz>, linux-kbuild@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] kconfig: warn if an unknown symbol is selected

Hi Yann,

On Tue, 2014-09-30 at 20:09 +0200, Paul Bolle wrote:
> A select of an unknown symbol is basically treated as a nop and is
> silently skipped. This is annoying if the selected symbol contains a
> typo. It can also hide the fact that a treewide symbol cleanup was only
> done partially.
> 
> There are also a few cases were this might have been done on purpose.
> But that anti-pattern should be discouraged. Almost all select
> statements point to a known and reachable symbol. So people will likely
> assume that any selected symbol is actually set. Selects that violate
> this assumption can only be spotted by checking multiple Kconfig files,
> often across architectures. It is unlikely that people will do this
> regularly.
> 
> So let's warn when we notice a select of a symbol that is not known in
> the configuration we're creating.
> 
> Signed-off-by: Paul Bolle <pebolle@...cali.nl>
> Acked-by: Michal Marek <mmarek@...e.cz>
> ---
> First sent as an RFC in https://lkml.org/lkml/2014/9/26/887 (and
> https://lkml.org/lkml/2014/9/26/886 for the cover letter).
> 
> Small modification to the commit explanation in comparison to the RFC,
> but identical patch. Minor edits to the cover-letter too.

I've gotten no reaction from you yet on this patch nor on the preceding
RFC. There have been a handful of other kconfig patches flying by the
last half year or so (at least, that I know of). None of those have
gotten any reaction from you, as far as I can tell.

Do you expect to handle this patch (and whatever has been submitted
lately by other people) in the near future?

>  scripts/kconfig/conf.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index fef75fc756f4..de8406287531 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -446,6 +446,45 @@ static void check_conf(struct menu *menu)
>  		check_conf(child);
>  }
>  
> +static void check_selects(struct menu *menu)
> +{
> +	struct symbol *sym, *sel;
> +	struct property *prop;
> +
> +	while (menu) {
> +		sym = menu->sym;
> +
> +		if (sym && !sym_is_choice(sym) &&
> +		    sym->type != S_UNKNOWN &&
> +		    sym->flags & SYMBOL_WRITE) {
> +			for_all_properties(sym, prop, P_SELECT) {
> +				sel = prop->expr->left.sym;
> +				if (sel->type == S_UNKNOWN &&
> +				    expr_calc_value(prop->visible.expr) != no) {
> +					fprintf(stderr, "%s:%d:warning: ",
> +						prop->file->name,
> +						prop->lineno);
> +					fprintf(stderr,
> +						"'%s' selects unknown symbol '%s'\n",
> +						sym->name,
> +						sel->name);
> +				}
> +			}
> +		}
> +
> +		if (menu->list) {
> +			menu = menu->list;
> +		} else if (menu->next) {
> +			menu = menu->next;
> +		} else while ((menu = menu->parent)) {
> +			if (menu->next) {
> +				menu = menu->next;
> +				break;
> +			}
> +		}
> +	}
> +}
> +
>  static struct option long_opts[] = {
>  	{"oldaskconfig",    no_argument,       NULL, oldaskconfig},
>  	{"oldconfig",       no_argument,       NULL, oldconfig},
> @@ -681,6 +720,8 @@ int main(int ac, char **av)
>  		break;
>  	}
>  
> +	check_selects(rootmenu.list);
> +
>  	if (sync_kconfig) {
>  		/* silentoldconfig is used during the build so we shall update autoconf.
>  		 * All other commands are only used to generate a config.

Regards,


Paul Bolle

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